From a1b04cc197e17c47b043051becb548dc8c60c886 Mon Sep 17 00:00:00 2001 From: Santosh Shilimkar Date: Mon, 11 Oct 2010 11:05:18 +0000 Subject: [PATCH] omap: serial: Fix the boot-up crash/reboot without CONFIG_PM The omap2plus_defconfig doesn't boot up when built with CONFIG_PM disabled on the latest linux-omap master. Below are the observations 1. OMAP3 reboots in the middle of boot -------------------------------------------------- [ 0.000000] Calibrating delay loop... 494.72 BogoMIPS (lpj=1933312) [ 0.000000] pid_max: default: 32768 minimum: 301 [ 0.000000] Security Framework initialized [ 0.000000] Mount-cache hash table entries: 512 [ 0.000000] CPU: Testing write buffer coherency: ok [ 0.000000] Brought up 1 CPUs [ 0.000000] SMP: Total of 1 processors activated (494.72 BogoMIPS). [ 0.000000] regulator: core version 0.5 [ 0.000000] NET: Registered protocol family 16 U-Boot 1.1.4 (Feb 11 2009 - 16:10:23) OMAP3430-GP rev 2, CPU-OPP2 L3-165MHz TI 3430SDP 1.0 Version + mDDR (Boot NOR) DRAM: 128 MB Flash: 128 MB NAND:128 MiB -------------------------------------------------- 2. OMAP4 does a kernel PANIC ------------------------------------- [ 0.000000] Calibrating delay loop... 1195.29 BogoMIPS (lpj=4669440) [ 0.000000] pid_max: default: 32768 minimum: 301 [ 0.000000] Security Framework initialized [ 0.000000] Mount-cache hash table entries: 512 [ 0.000000] CPU: Testing write buffer coherency: ok [ 0.000000] L310 cache controller enabled [ 0.000000] l2x0: 16 ways, CACHE_ID 0x410000c2, AUX_CTRL 0x0e050000 [ 0.000000] CPU1: Booted secondary processor [ 0.000000] Brought up 2 CPUs [ 0.000000] SMP: Total of 2 processors activated (2395.78 BogoMIPS). [ 0.000000] regulator: core version 0.5 [ 0.000000] NET: Registered protocol family 16 [ 0.000000] mux: Could not set signal i2c2_scl.i2c2_scl [ 0.000000] mux: Could not set signal i2c2_sda.i2c2_sda [ 0.000000] mux: Could not set signal i2c3_scl.i2c3_scl [ 0.000000] mux: Could not set signal i2c3_sda.i2c3_sda [ 0.000000] mux: Could not set signal i2c4_scl.i2c4_scl [ 0.000000] mux: Could not set signal i2c4_sda.i2c4_sda ------------------------------------- This is happening because 'omap_serial_init()' is hanging in the boot. On OMAP3 the watchdog is generating reboot because devices_init doesn't happens where as on OMAP4 it just hangs without reboot. The uart clock is not getting enabled after omap_device_idle as part of omap_serial_init. The omap_device_idle(will disable the clock) then omap_uart_block_sleep() should enable clock back disabled during the boot up phase. But omap_uart_block_sleep() stuffed version is binded only under CONFIG_PM and other version is just empty. Hence it is not enabling clock back as expected This patch adds uart clock enable code to omap_uart_block_sleep() function built with CONFIG_PM disabled. Thanks to Charulatha and Govindraj for their help on this debug. Signed-off-by: Santosh Shilimkar Signed-off-by: Charulatha V Signed-off-by: Govindraj.R Acked-by: Kevin Hilman Signed-off-by: Tony Lindgren --- arch/arm/mach-omap2/serial.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/serial.c index 338e46a844a4..ba8a5cc8eae8 100644 --- a/arch/arm/mach-omap2/serial.c +++ b/arch/arm/mach-omap2/serial.c @@ -608,7 +608,11 @@ static DEVICE_ATTR(sleep_timeout, 0644, sleep_timeout_show, #define DEV_CREATE_FILE(dev, attr) WARN_ON(device_create_file(dev, attr)) #else static inline void omap_uart_idle_init(struct omap_uart_state *uart) {} -static void omap_uart_block_sleep(struct omap_uart_state *uart) {} +static void omap_uart_block_sleep(struct omap_uart_state *uart) +{ + /* Needed to enable UART clocks when built without CONFIG_PM */ + omap_uart_enable_clocks(uart); +} #define DEV_CREATE_FILE(dev, attr) #endif /* CONFIG_PM */ -- 2.39.2